Method of making steel spring-washers.



J. E. WILSON.

METHOD OF MAKING STEEL SPRING WASHERS. APPLICATION FILED MAR.15, 1910.

978,974. Patented Dec .20, 1910.

wmvssszs: INVENTOR Jzs.E. Wilson.

' I BY gi/ bro/my edge, in order to form steel spring washers,

N T T E PAETENT OFFICE.

JAMES E. WILSON, OF NEW. YORK, N. Y., ASSIGNOR TO THE NATIONAL LOCK WASHER 00., OF NEWARK, NEW JERSEY, A CORPORATION OF NEW JERSEY.

ME'1HOD OF MAKING STEEL SPRING-WASHERS.

will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to certain new and useful improvements in and relating to method of making steel sprin washers, and

consists inthenovel steps an method here-- inafter fully described and then particularly pointed out in the claim which concludes this description.

Heretofore, in the manufacture of spring washers of tempered steel made from severed convolutions of spiral coils such coils being wound from various forms of rod or wire the mostcommon of which are of square or rectangular cross section, much difliculty has been experienced owingtothe.

fact that the sharp corners at the outer,

edges of these convolutions would crack or fleck sufficient to invite fracture of the Washers after they have been subjected to heat treatment such as hardening and tempering, and this fiecking or cracking is due to the extensions or stretching of the steel in winding it about the mandrel to form the. spiral coil. No material fiecking or craekin appears at the inner edges of the spiral 001 since the steel undergoes a swaging operation at these points more or less marked according tothe temper of therod since the latter may not be of uniform temper throughout its length. Various exp'edientshave been'employed to obviate these difficulties,

all more or less uncertain, and the object of my present improvement is to so form the rod or strip before winding as to preventany' fiecking or cracking at the outer edges of the completed coil. A keystone shape'in cross section of rod has been used, but it does not obviate the slight ruptures heretofore mentioned.

Naturally, in winding steel stock on its the stretching upon the outer. surfaces .of

Specification of Letters 1atent. Patented Dec, 20, 1910,

I Application filed March 15, 1910. "Serial No. 549,421.

the coil thus formed is excessive, and the slight rupture at the outer edges of the coils proves a damage to the finished product; I therefore form the rod, which maybe square, rectangular or keystone in cross section, slightly round or convex at the corner portions which form the outer edges of the completed coil, and I have found by this method 'that I eliminate all the difiiculties heretofore-mentioned, even when the material is almost too hard to wind.

In the accompanying drawing Figure '1 illustrates an edge elevation of the stock before winding and after the same has been rolled in accordance with my method-Fig.

2 a cross section of such stock-Fig. 3 an elevation of the completed coilF1g. 4 a cross sect-ion taken through one side of one of the coils, and Fig. 5 is an isometric view of the spring washer formed by. severing one of the coils.

Similar numbers of reference denote like partsin theseveral figures of the drawing. In carrying out my improvement I roll the stock in such manner that it is. preferably keystone shape in cross section and has convex surfaces which connect the side faces ofthe stock with the edges thereof, and in numeral 6 at Fig. 3, the inner edge 4 constituting the inner faces of the coils while the outer edge 3' forms the outer surfaces of said coils, v I prefer to round the edge portions at the surface 4 because a more symmetrical product is thereby obtained, al-- though this rounding does not affect the product in any way and these edges can be left sharp, if desired. During this process of winding the strip the inner or narrow edge thereof will be subjected to a s'waging operation while the outer or wider edge will undergo a stretching process such as hereinbefore referred to and explained, and the effect of this swaging and stretching is to slightly increase the thickness of the inner edge t and to slightly decrease the thickness of the outer edge 3 and this will cause the side faces of the coils to become parallel and to be disposed at right angles to the inner and outer faces as clearly shown at Fig. 4, While at the same time the edges will be slightly rounded.

As I said before, the rounding of the edges of the stock which forms the inner faces of the coils is immaterial, but the rounding of the edge portions which appear at the outer faces of the coil is most important since all flecking or fracture incidental to the coiling is thereby prevented, so that when the washers are severed from the coil and subjected to hardening and temper they will stand any amount of compression Without breaking.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

- The herein described method of making steel spring washers, which consists in rolling the stock into a suitable shape in cross section and forming convex surfaces atedges thereof, winding such stock into the form of a spiral coil with the convex surfaces at the outer edges of the convolutions of such coil, and finally severing each of said convolutions.

In testimony whereof I aflix my signature in presence of two witnesses.

JAMES E. \VILSON.

Witnesses:

ROBERT D. REYNOLDS, NEWTON P. KINSEY. 

